* {
    padding-top: 15px;
    margin: 0;
    font-size: 16px;
    word-spacing:27px; /* 控制字与字之间空格的宽度 */
}

.center {

    margin: auto;
    width: 500px;
    height: 350px;

    border: 2px solid black;
}

.center h2 {

    margin-left: 180px;
}

.center h3 {
    margin-left: 20px;
    margin-top: 5px;
}

#per {
    color: red;
}

.centerin {
    width: 300px;
    height: 200px;

    background-color: #ffd7a7;
    margin: auto;
    margin-top: 20px;
    border-radius: 40px 40px;
}